A light-emitting diode often can provide light in a more efficient manner than an incandescent light source and/or a fluorescent light source. The relatively high power efficiency associated with LEDs has created an interest in using LEDs to displace conventional light sources in a variety of lighting applications. For example, in some instances LEDs are being used as traffic lights and to illuminate cell phone keypads and displays. Many technological advances have led to the development of high power LEDs by increasing the amount of light emission from such devices.
Typically, an LED is formed of multiple layers, with at least some of the layers being formed of different materials. In general, the materials and thicknesses selected for the layers influence the wavelength(s) of light emitted by the LED. In addition, the chemical composition of the layers can be selected to promote isolation of injected electrical charge carriers into regions (commonly referred to as quantum wells) for relatively efficient conversion to optical power. Generally, the layers on one side of the junction where a quantum well is grown are doped with donor atoms that result in high electron concentration (such layers are commonly referred to as n-type layers), and the layers on the opposite side are doped with acceptor atoms that result in a relatively high hole concentration (such layers are commonly referred to as p-type layers).
Traditional light-emitting devices may have complex packages which may require multiple manufacturing steps in order to form a packaged LED. For example, as shown in FIG. 1, a light-emitting structure 100 may include a light-emitting diode 102 and a transparent layer 103 (e.g., a window) supported by a package 104. Typically, contacts 106 can be attached via solder or electrically conductive adhesive 108 to the package 104. The contacts 106 can be disposed between the package and a supporting structure 110 (e.g., core board). The package 104 can include electrically conductive vias 124 (e.g., metal-filled vias). Additionally, some light-emitting structures incorporate an electrically isolating dielectric material 112 between the support structure and the circuit board contacts.
Light-emitting devices also generally include one or more electrical contact bond pads 114 (also known as electrodes) which are features on a device that may be electrically connected via wire bonds 116 to a wire bond pad contact 118 which in turn can receive power from a power source (not shown). Typically, wire bonds 116 are soldered 120 to the wire bond pad contacts 118 and the electrical contact bond pad 114, as illustrated in FIG. 2. Electrical current can be provided from the power source to the device via the wire bond pads 118 and electrical contact bond pad. In addition, the electrical contact bond pad 114 can include current spreading members 122 (e.g., metal fingers) which are capable of delivering current along the lengths thereof and to the surface of the LED 102.
The complexity of such LED devices and multiple manufacturing steps involved in fabricating such devices inevitably increases production time and costs. Further, the wire bonds tend to have small diameters which further can add to the fabrication complexity and production time. Also, the wire bonds can be current limiting due to their small diameters.